Field Config: Add new units (mΩ, kHz, MHz, GHz, ac, ha)

[Develer]

What is this feature?

Added the following new units:

• Milliohm (mΩ) unit was added to the list of units
• Kilohertz (kHz)
• Megahertz (MHz)
• Gigahertz (GHz)
• Acres (ac)
• Hectares (ha)

Why do we need this feature?

There are scenarios that need additional units on axes.

Which issue(s) does this PR fix?:

Fixes #70680

Special notes for your reviewer:

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.

[grafana-delivery-bot]

Hello @Develer!
Backport pull requests need to be either:

• Pull requests which address bugs,
• Urgent fixes which need product approval, in order to get merged,
• Docs changes.

Please, if the current pull request addresses a bug fix, label it with the type/bug label.
If it already has the product approval, please add the product-approved label. For docs changes, please add the type/docs label.
If the pull request modifies CI behaviour, please add the type/ci label.
If none of the above applies, please consider removing the backport label and target the next major/minor release.
Thanks!

[grafana-delivery-bot]

Hello @Develer!
Backport pull requests need to be either:

• Pull requests which address bugs,
• Urgent fixes which need product approval, in order to get merged,
• Docs changes.

Please, if the current pull request addresses a bug fix, label it with the type/bug label.
If it already has the product approval, please add the product-approved label. For docs changes, please add the type/docs label.
If the pull request modifies CI behaviour, please add the type/ci label.
If none of the above applies, please consider removing the backport label and target the next major/minor release.
Thanks!

[nmarrs]

Great job on this! I think we may want to consider addressing the other user requested units from the same issue in terms of adding various other units (especially hertz).

As part of this we should test / verify that autoscaling can be supported (i.e. 3000 ms -> 3s etc.)

[nmarrs]

Great work!